Insights Into the Morphological Analysis, Phytochemical Profile and Antimicrobial Activities of the Multi-Walled Carbon Nanotubes-Induced In Vitro Sugarcane

The present research work reports the impact of multi-walled carbon nanotubes (MWCNTs) on sugarcane morphological characteristics, the production of secondary metabolite (SMs), and the antimicrobial activity of sugarcane callus culture in vitro. Explants (young leaf sheaths and leaf rolls) of usually smaller diameter were cultured on Murashige and Skoog (MS) medium following our previous protocol for sugarcane callogenesis. The induced calli were subjected to varying concentrations (1, 2, 3, 4, and 5 mg/l) of MWCNTs for multiplication. The highest multiplication was recorded on media containing 5.0 mg/l of CNTs with fresh weight 2.8567 g. Different concentrations (0, 5, 10, 15 and 20 mg/l) of MWCNTs were applied to regenerate the calli cultures. The highest number of shoots and roots were developed on 15.0 mg/l, while the highest shoot and root length (in centimeter) were observed on the highest used concentration, i.e. 20.0 mg/l CNTs. Similarly, the sub-cultured calli were subjected to phytochemical analysis and the effect of MWCNTs on amount of biochemical contents like total phenolic contents, flavonoids, saponins and terpenoids was determined. The highest contents were found in the culture containing the highest concentration of CNTs, in all cases. Moreover, the antioxidant activities of the MWCNTs induced in vitro sugarcane were also evaluated by the 1,1 diphenyl 2, picryl hydrazyl (DPPH) methods, which was found highest, i.e. 95.556% with EC50 value of 34.49 µg/ml for crude extract of callus grown on MS-media containing 5.0 mg/l MWCNTs. The antimicrobial activity was evaluated against two bacterial pathogens, Clavibactor michiganensis subsp. michiganensis (CMM) and Ralstonia solanacearum (RS) with inhibition zone of 14 mm in case of CMM, while 17 mm was measured against RS Spp. Our results reveal that using MWCNTs in specific concentrations could act as a plant growth promotor and novel elicitor for the in vitro biosynthesis of useful SMs with antimicrobial activity against broad spectrum microbial pathogens.